Apparatus for distilling liquids



y 23, 1939- A. R. NEVITT 2,159,566

APPARATUS, FOR DISTILLING LIQUIDS Filed Sept. 24, 1936 2 Sheets-Sheet l I? h Ml- 90 I 51 Fun!!! 6- 75 Inventor fleyz'zf Attorney May 23, 1939.

A. R. NEVITT 2,159,566

APPARATUS FOR DISTILLING LIQUIDS Filed Sept. 24, 1936 2 Sheets-Sheet 2 2: Attorney Patented May 23, 1939 PATENT OFFICE APPARATUS FOR- DISTILLING LIQUIDS Albert R. Nevitt, Montreal, Quebec, Canada Application September 24, 1936, Serial No. 102,376

3 Claims.

The present invention relates to the art of distilling liquids and has particular reference to an apparatus for distilling hydrocarbon oils.

--'An object of the invention is the provision 5 of an apparatus for distilling liquids which enables accurate separation of the fractional dis- 'tillates.

. Another object of the invention is the provision of an apparatus for distilling liquids which enable overlapping of the various boiling point fractions.

A further object of the invention is the provision of an apparatus of the aforesaid character designed to enable the recovery of a high yield of distillates boiling within relatively narrow limits.

Still another object of the invention is the provision of anapparatus of the above character which is highly efiicientin operation.

Other objects and advantages of the invention will become apparent as the description progresses,

In the accompanying drawings forming a part ofthis specification and in which like reference characters are employed to designate corresponding parts throughout the same:

. Figure 1 is a top plan view of the assembled apparatus,

, Figure 2 is a side elevational view of the same partly broken away to illustrate interior construction,

Figure 3 is a transverse section taken on the line 33 of Figure 2,

Figure 4 is a vertical section through one of the fractionating towers,

: Figure 5 is a similar enlarged section of another fractionating tower,

: Figure 6 is a fragmentary perspective view through one of the towers, and

' Figure '7 is an enlarged fragmentary section through one of the heating coils.

1 Referring to the drawings, wherein for the purpose of illustration is shown a preferred embodiinent of the invention, B generally designates a horizontal elongated furnace having positioned centrally therein a horizontal cylindrical retort Within the upper portion of the furnacejat each side of the retort ID, are mounted longi- 50 tudinally extending coils C and D, each embodyables, continuous operation and avoids objection front and rear end walls of the furnace and through the inner end wall of the drum-shaped end headers l3.

In the bottom of the furnace are mounted suitable burners I5 adapted to project flames in the lower portion thereof below the retort l0 and the side coils C and D.

At longitudinally spaced positions on the retort I0 are mounted a plurality of, in the present instance three, upstanding towers E, F and G, each embodying a cylindrical shell l1 communicating with the interior of the retort through an opening H! at the top of the retort registering with the base of the tower shell. In each of the tower shells I! are mounted horizontal, vertically spaced partitions or trays 2|], 2|, 22, 23, 24, 25 and 26. Each of these partitions is formed with an elongated aperture or slot formed at the edges with upstanding walls providing relatively narrow vertical passages 21. Over each passage 21 is loosely fitted an elongated hood 28 resting on the top of the partition and having outlet slots 29 at the bottom, these hoods providing bafiies to deflect gases and vapors passing through the liquid on the partitions. A number of the partitions or trays are formed with downwardly ofiset marginal wells 30. Vertically arranged overflow pipes 3| are disposed to conduct liquid from each superposed tray to one immediately therebelow. This construction provides bubbling traps on each partition or tray and means for conducting the liquid, when it attains a predetermined level, from each tray to the one next below the same. A tube 32, attached to the bottom tray 20 of the tower E, extends downwardly into the retort so as to convey the overflow liquid from this tray to the bottom of the retort.

A conduit 35 connects the bottom tray 20 of the tower G with the inlet header I3 of the heating coil D to convey overflow liquid from this tray into the coil. The outlet end of this coil connects with the bottom tray 20 of the tower F through the medium of a pipe line 36. A line 3! connecting with the opposite side of the tray 20 of tower F connects with the inlet end of the coil C. The outlet of this latter coil connects with a well in the bottom tray 20 of the tower E through the medium of a pipe line 38.

During operation, the liquid, in the present example a crude petroleum oil, is forced into the system through a supply pipe by means of a pump 4| through a regulating valve 42 and a float control meter 43 and is conducted successively through a plurality of heat exchangers 44, 45 and 46, preferably at the rate of 40 barrels an hour and at a pressure of 400 lbs. per sq. in. From the heat exchanger 46, the oil is conducted through a pipe line 41 into the well 30 of the bottom tray 20 of the tower G, attaining a temperature of about 400 F. by passage through the heat exchangers. The vaporized portion of the product from the exchangers passes upwardly through the bubble traps in the superposed trays in the tower, each of these trays carrying liquid to a predetermined height so that condensation is effected on each tray. The temperature of the liquids on the trays is controlled by the introduction of fluid through a feed line 48 discharged into the top of the tower through a manifold under pressure of a pump 49.

The lightest fraction of the crude oil, which in the present case constitutes about 10% of '74 A. P. I. gravity, passes upwardly through all of the trays and is released through the line havinga pressure relief valve 52 set at a pressure of 375 lbs. per sq. in. and is conducted through the condenser 45 and discharged to a suitable storage tank by means of a pump 53. The next fraction, which consistsof approximately 24%, is a gasoline fraction of 62 A. P. I. gravity and collects on the tray 24 of tower G; from whence it is drawn off by a pump 55 in a take off line 56 and passed through the condensers 46 from whence it is carried to a storage tank by a take off line equipped with" a valve 51. The next fraction of the product drawn into the bottom tray, which constitutes about 8% and is of a naphtha 54 A. P. I. gravity, is collected in the trays 22' and 23 and flows downwardly through the overflow pipes into the tray 2! and it is conducted from the well of this tray through a. conduit 59 'and'througha valve 60, passes through the condenser 44 and'is carried to a storage tank through an outlet conduit equipped with a pump 6|. The remainder of the crude oil, which constitutes about 58% of the charge, overflows through the pipe 35and is forced'by a pump 35' through a control valve62 into the coil D. The oil conducted through this coil is heated therein by the burners to a temperature of about 750 F. and is discharged through the conduit 36 and delivered onto the bottom tray 20 or the tower F. i

The headed vapors rise upwardly through'the trays in the tower F so that the lightest vapor which constitutes about 12% 'of the original charge passes out through an outlet pipe 64 equipped with a relief valve 65 and is conducted through a condenser 66 from which it is conveyed to a storage tank. This fraction constitutes a kerosene cut of 48 A. P. I.'gravity. The heaviervapors collect on the upper trays 25 and 26' and flow 'throughthe overflow pipes downwardly onto the tray 24 from whence the liquid is carried off through a pipe line '61 controlled by a relief valve 68 and passed through a condenser from which it is conducted to a storage tank through a discharge line! I. This last fraction constitutes a light gas-oil'cut of about 36 A. P. I. gravity and is about 10% of the original charge; The next fraction whichis an overflow from the trays 23and 22 collects on the tray 2| and is conducted, by a pipe line 12; through a condenser l3'and discharged toa storage tank through an outlet line 14. This fraction is a heavy gas-oil cut of 36 A. P. I. gravity and is about 10% of the original charge. The excess overflow is withdrawn from the bottom tray 20 and is conducted through the medium of the therefrom through the top outlet pipes.-

pipe 31 to the inlet end of the furnace heating coil C.

The heavier portion of the oil, conducted through this coil, is heated to a temperature of about 830 F. and constitutes about 36% of the original charge. From the outlet end of the coil, this product is conducted through the pipe 38 to the bottom tray 20 of the tower E. The distillation is continued in this tower in the. manner described relative to the towers F and G,thelightest vapors which constitute a light neutral oil of 28 A. P. I. gravity are conducted from the top of the tower through a pipe 16 to a condenser 11. The next fraction, which constitutes a wax distillate, is taken from the tray 24, which collects theoverflow from the superposed trays 25 and 26, and is carried off through a line 18 to a condenser 19. Another fraction collects on the tray 2! and is an overflow from the trays 22 and 23 and constitutes a cut of about 12% which is drawn from the well of the tray 2| through a line 80 to a condenser 8|. The residue accumulating on the bottom tray' 20 of the tower E passes downwardly through the tube 32 into the retort I 0, where it is heated by the furnace burners and also by steam admitted into a pipe-'83 extending longitudinally in the lower portion of theretort connected'with a steam supply conduit 84. The pipe 83 is formed, at longitudinally spaced intervals, with a plurality of bottom outlets disposed to discharge'the steam onto the bottom of the retort. Thus, the fluid in the retort is heated to a temperature of about 950 F.

Due to the slow vaporization of. the residue-in the retort, some cracking of theoil is likely to occur, evolving light vapors of the gasoline series which rise through the towers and are conducted In order to efiect suitable separation of'the distillates issuing from the top outlets, and which may contain some cracked light vapors, they'are conducted, from the tower F, through the outlet pipe 64, through the condenser 66' and through the shell of the condenser 10 through the'medium of the pump 85, so as to raise the temperature above the boiling point of some of the lighter constituents. This mixture is conducted from the condenser 10 into a flash chamber'fl'l'. The liquid portion separated in the chamber '81 is carried off through the bottom line 88. The light vapors from this chamber are conducted through a line 89, so as'to connect with the'line 5| from the tower G and pass through the condenser 45' where they are blended with products of the same series. I

The vapors passing from'the top of the tower E are conducted by the line 16 through the condenser 11 and pass from the same through a line 90 and through the shell of "the condenser 8| which raises the temperature thereof. From the condenser 8|, the mixed liquid and vapors are, conducted by an outlet pipe 9| to'asecond flash chamber 82, the liquid portions being carried to a storage tank through a bottom outlet line 93, while the light vapors are conducted through a'line 94 and the line 5| through the condenser 45.

From the foregoing it will be appreciated that the invention is capable of continuous operation and will enable high yield distillation resulting in close boiling relatively pure fractions obtained with great efficiency. It will be understood that the operating conditions, such as temperatures and pressures, stated in the foregoing may be varied to suit conditions of the various fluids which may be treated in practice and that various modifications of the structure of the apparatus may be resorted to without departing from the spirit of the invention or the scope of the subjoined claims.

Having thus described my invention, I claim:

1. In distilling apparatus of the character described, a retort, three fractionating towers mounted in spaced relation on the retort and communicating with the interior thereof, a plu rality of vertically spaced trays mounted in each of the fractionating towers provided with bubble traps, a pair of heating coils mounted adjacent the retort, means for heating the retort and heating coils, an inlet conduit connecting the bottom tray of one of the end towers with the inlet of one heating coil, an outlet conduit connecting the outlet end of the said coil with the bottom tray of the intermediate tower, a conduit connecting the last mentioned tray with the inlet end of the second heating coil, a conduit connecting the outlet end of the said second coil with the bottom tray of the third tower, means 'for feeding charging stock onto the bottom tray of the first mentioned tower, and means for removing fractional distillates from top outlets in thetowers and from intermediate trays therein.

2. In distilling apparatus of the character described, a retort, three fractionating towers mounted in spaced relation on the retort and communicating with the interior thereof, a plurality of vertically spaced trays mounted in each of the fractionating towers provided with bubble traps, a pair of heating coils mounted adjacent the retort, means for heating the retort and heating coils, an inlet conduit connecting the bottom tray of one of the end towers with the inlet of one heating coil, an outlet conduit connecting the outlet end of the said coil with the bottom tray of the intermediate tower, a conduit connecting the last mentioned tray with the inlet end of the second heating coil, a conduit connecting the outlet end of the said second coil with the bottom tray of the third tower, a conduit having communicative connection with the last mentioned tray extending to the bottom portion of the retort to conduct fluid from the said tray into the retort, means for feeding charging stock through a plurality of heat exchangers and onto the bottom tray of the first mentioned fractionating tower, and means for removing fractional distillates from the top and from intermediate trays of each of the said fractionating towers.

3. In distilling apparatus of the character described, a retort, a plurality of fractionating towers mounted on the retort and having communication with the retort, a plurality of trays mounted in the said fractionating towers, a plurality of heating coils mounted adjacent the retort, means for heating the retort and coils, a conduit connecting the tray of one of the towers with the inlet of one heating coil, a conduit connecting the outlet end of the said coil with the tray of a second tower, a conduit connecting the last mentioned tray with the inlet end of a second coil, a conduit connecting the outlet end of the said second coil with the tray of a third tower, means for feeding charging stock onto a tray of the first mentioned tower, and means for removing fractional distillates from the said towers.

ALBERT R. NEVI'I'T. 

